[MatjazO]

Of course. But as BC already pointed out: at least for me, the focal length and the aperture (or the corresponding DOF) are my main settings I adjust on the camera to create the effect I want. Sometimes shutter speed, too, if it's about freezing motion (or the contrary, when panning for example).

Sure. 😉 Honestly this are pretty simple things, arent they? These one can - if he or she is wiiling to - learn pretty fast.


In case of equivalency, it is about few simple equations, for god’s sake. Of course it is correct as a concept. And of course it is useful if comparing different systems. But all of us have made a choice of a system, for whatever different reasons. And when going out with the system of your choice, what you have in your hand is what takes pictures, together with your skills, and there equivalent photograph is less then meaningless.

[JJ_SO]

No one was hammering anything. Others were trying to scale an apple to a pineapple. Same characters in the word, just a bit more. Anyone who sees any benefit in his or her photography by knowing theoretical nerdy stuff? Anyone believing a D3x with 24 MP will allow two steps more ISO than one of these days 24 MP APS-C sensors of, say,  a D7200? Witch a credible proof, not only more nerd blurb.

 

Gaining 2 stops just because it's "a" FF is a bit daring to say. Some FF gain, others much less so:

 



 

It's not to prove something or somebody wrong, I'd just be careful to generalize in this already very unscientific debate  ^_^

 

Also, investing the time we lost now in learning to deal better with our cameras could be an idea... at the end the picture counts and no one looking at it will waste any time to make equivalencing calculations. The concept takes too many things for granted and perfectly scalable.

[Brightcolours]

Focussing on noise is a bit... besides the point, to be frank. A Nikon D70 is more noisy than a Nikon D500. Yet no one objects to using equivalent settings between those (iow: same FOV, same DOF... Same focal length, same f-value). Everyone will accept that one uses 35mm for a more or less "normal" FOV, and f1.8 for a more or less shallow DOF. No one will point out that that is a flawed concept, because of image will be noisier than the other because of different sensor generations.

[JJ_SO]

I sense a bit of a lack of unity in opinion in the monastery St. Equivalencia: One dude tells me, FF gains 2 stop compared to µ 4/3. In the scientific equation of that matter sensor age didn't play much of a role... Now the other dude comes jumpin' and talks about a difference between a stone age Nikon D70 and a D500, less stone age. Hmmm.

 

I just was looking for some kind of visible proof since every equivalence monk here keeps on swinging the rosary but doesn't put much effort in delivering samples - okay, to be fair, you could deliver what you want. If there's already a clearly visible weakness in the ISO theory, I just turn my back and go on with funnier things. Like tax declarations or so The equation is alright. In theory. And in reality, it's one of these "in ideal conditions" constructions which just don't meet reality. And reality appears to sho no interest in meeting the equation so I just like to keep both happy and continue with not caring. 

[mst]

One dude tells me, FF gains 2 stop compared to µ 4/3. In the scientific equation of that matter sensor age didn't play much of a role...

Wait a bit, and let that dude quote himself:
 

My point was: you're ignoring ISO, because on the full frame camera (assuming similar resolution and sensor on roughly the same engineering level
), you just bump up ISO by two stops, because that will lead to the same image quality in terms of noise and result in the same shutter speed, too.

Of course the two cameras you mentioned (D3x, D7200) do NOT qualify here. I happen to know very well from theory and practice

In this context though, (again) recommended reading:

http://www.photozone.de/Reviews/986-equivalence

Klaus explains things in there very well.

There is no "one truth" in this discussion. There are a few basic facts which lead to the theory of equivalency (in terms of DOF, FOV and ISO). This is honestly just physics (and not the rocket science kind). There are of course many parameters that you can not calculate in, because in the end no two camera sensors are really 100% comparable, just as two lenses aren't, even if their specs are very close or even identical on paper (otherwise this site obviously wouldn't exist).

It's a personal matter of taste how much you take from the equivalency equations or if you even care about it at all. It does, however, give you an estimate (and a fairly good one), what to expect in general if you intend to compare systems. For some the drawbacks of a smaller sensor might be ok in daily life or even welcome (talking about DOF for example), for others, they are a major concern and a reason to not consider m43 (count me in here).

[Brightcolours]

I sense a bit of a lack of unity in opinion in the monastery St. Equivalencia: One dude tells me, FF gains 2 stop compared to µ 4/3. In the scientific equation of that matter sensor age didn't play much of a role... Now the other dude comes jumpin' and talks about a difference between a stone age Nikon D70 and a D500, less stone age. Hmmm.

 

I just was looking for some kind of visible proof since every equivalence monk here keeps on swinging the rosary but doesn't put much effort in delivering samples - okay, to be fair, you could deliver what you want. If there's already a clearly visible weakness in the ISO theory, I just turn my back and go on with funnier things. Like tax declarations or so The equation is alright. In theory. And in reality, it's one of these "in ideal conditions" constructions which just don't meet reality. And reality appears to sho no interest in meeting the equation so I just like to keep both happy and continue with not caring. 

How many stops does the OM-D E-M10 mk II gain compared to a E-300? Both have same sized sensors. You are just looking for straw man arguments...

 

Lens equivalence is not about ISO settings and noise. It is about the FOV and the aperture.

And when someone, for some valid reason or just for the sake of trolling about how lens equivalence does not compute, needs to have exposure times also the same, you can just set an equivalent ISO setting. Setting equivalent ISO settings accomplishes two things: similar exposure times, and similar amount of light captured by the sensors.

 

And when you set an equivalent ISO setting, what Markus points out comes in: similar sensor technology sensors will give similar noise with equivalent ISO settings.

 

And when someone brings up how "diffraction always sets in at f8", we try to explain how that is wrong on any way you look at it, and that also diffraction adheres to the laws of physics, and also scale with the crop factor and don't collide with lens equivalence theory.

 

And then, anti-equivalence trolls will think of something else again to troll. Does not make the simple theory of lens equivalence any less valid

[JJ_SO]

No BC, I'm not looking for straw man arguments, I'm basically following the ones I read before - and there was the generalisation that a FF sensor, no matter what, gains about 2 stops of light. I know it has to be sort of same generation sensors, but that wasn't said - it's just that all of these simple equivalencing calculations fail with reality of so different sensors, RAW-converters and also to say this lens is just that other lens, only slower and longer - misleading and  not helpful.

 

There is no camera which is the exactly scaled version of a smaller or bigger one. Therefore you have a nice formula, one just needs to build teh devices fullfilling it.

[Brightcolours]

An FF sensor caches the same light at equivalent settings. Old FF sensors are noisier at higher ISOs than new FF sensors. 

 

Again, how noisy a sensor is has nothing at all to do with lens equivalence. Lens equivalence is about how DOF and FOV translate from format to format. And if one for whatever reason looks for catching the same amount of light/similar exposure time, use equivalent ISO settings. That is all. 

 

Not about noise in images, not about bokeh rendering, not about how sharp a particular lens is, or how soft, not about astigmatism or coma or other lens aberrations.

[mst]

...and there was the generalisation that a FF sensor, no matter what, gains about 2 stops of light. I know it has to be sort of same generation sensors, but that wasn't said...

 

Come on, please! It was said, see above.

There is no camera which is the exactly scaled version of a smaller or bigger one. Therefore you have a nice formula, one just needs to build teh devices fullfilling it.

As is the case with any generalizing and thus idealizing rule. Yet, it's still a rule, and it's up to you to derive decisions from it and apply them to a world that is more complicated than the rules assume.

[JJ_SO]

In the screenshot I showed I used DPReview's comparison tool. Olympus OM D-E M1  MkII and Sony Alpha 7 and I saw a pretty big gap in the noise behaviour. Now, as Olympus is not making FF anymore and we are not in a special equivalence thread (although a lot of threads show this unpleasant kind of pointless nerdiness) I just set one to 1600 ISO and the otehr 2 steps above. Panasonic GH5 and Canon 6D are confirming the "two steps higher ISO - no problem" theory, the Oly and Sony combination less so.

 

A theory which needs so specific conditons to work as posted - is that practical?

 

Especailly cross comparing µ 4/3 and FF worlds where lenses are very different, aimed at a different audience? And reasoning with not even available 400/5.6 lenses, to what will that lead? If the answer is not "to a better picture", you really can keep that knowledge and frame it to hang it somewhere.

 

For what is a comparison good if there are no alternatives? One who has a µ4/3 system will not go and run for a non-existing tele-lens and buy a body for it as well. The lens is not made to compete current 400 mm FF lenses. It is one for the needs of µ 4/3 owners. To degrade it the way "it is only equivalent to blabla..." and compare it's price to extremely outdated glass is throwing a lot of fog and a lot of blurb. If the lens is not good, it's too expensive. If it's good, then it has a price which is still a lot cheaper than 400/4 FF lenses. Depending on the compared cameras, it will not look worse than some FF stuff. That's bascially all what one needs to know. Everything else about equivalence is a waste of time.